1 /* xscreensaver, Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999
2 * by Jamie Zawinski <jwz@jwz.org>
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation. No representations are made about the suitability of this
9 * software for any purpose. It is provided "as is" without express or
13 /* This file contains some code for intelligently picking the best visual
14 (where "best" is biased in the direction of either: high color counts;
15 or: having writable color cells...)
19 #include "resources.h" /* for get_string_resource() */
22 #include <X11/Xutil.h>
24 extern char *progname;
28 # define isupper(c) ((c) >= 'A' && (c) <= 'Z')
31 # define _tolower(c) ((c) - 'A' + 'a')
35 static Visual *pick_best_visual (Screen *, Bool, Bool);
36 static Visual *pick_mono_visual (Screen *);
37 static Visual *pick_best_visual_of_class (Screen *, int);
38 static Visual *pick_best_gl_visual (Screen *);
39 static Visual *id_to_visual (Screen *, int);
40 static Visual *id_to_visual (Screen *screen, int id);
43 #define DEFAULT_VISUAL -1
44 #define BEST_VISUAL -2
45 #define MONO_VISUAL -3
46 #define GRAY_VISUAL -4
47 #define COLOR_VISUAL -5
49 #define SPECIFIC_VISUAL -7
52 get_visual (Screen *screen, const char *string, Bool prefer_writable_cells,
55 char *v = (string ? strdup(string) : 0);
62 for (tmp = v; *tmp; tmp++)
63 if (isupper (*tmp)) *tmp = _tolower (*tmp);
65 if (!v || !*v) vclass = BEST_VISUAL;
66 else if (!strcmp (v, "default")) vclass = DEFAULT_VISUAL;
67 else if (!strcmp (v, "best")) vclass = BEST_VISUAL;
68 else if (!strcmp (v, "mono")) vclass = MONO_VISUAL;
69 else if (!strcmp (v, "monochrome")) vclass = MONO_VISUAL;
70 else if (!strcmp (v, "gray")) vclass = GRAY_VISUAL;
71 else if (!strcmp (v, "grey")) vclass = GRAY_VISUAL;
72 else if (!strcmp (v, "color")) vclass = COLOR_VISUAL;
73 else if (!strcmp (v, "gl")) vclass = GL_VISUAL;
74 else if (!strcmp (v, "staticgray")) vclass = StaticGray;
75 else if (!strcmp (v, "staticcolor")) vclass = StaticColor;
76 else if (!strcmp (v, "truecolor")) vclass = TrueColor;
77 else if (!strcmp (v, "grayscale")) vclass = GrayScale;
78 else if (!strcmp (v, "greyscale")) vclass = GrayScale;
79 else if (!strcmp (v, "pseudocolor")) vclass = PseudoColor;
80 else if (!strcmp (v, "directcolor")) vclass = DirectColor;
81 else if (1 == sscanf (v, " %ld %c", &id, &c)) vclass = SPECIFIC_VISUAL;
82 else if (1 == sscanf (v, " 0x%lx %c", &id, &c)) vclass = SPECIFIC_VISUAL;
85 fprintf (stderr, "%s: unrecognized visual \"%s\".\n", progname, v);
86 vclass = DEFAULT_VISUAL;
89 if (vclass == DEFAULT_VISUAL)
90 result = DefaultVisualOfScreen (screen);
91 else if (vclass == BEST_VISUAL)
92 result = pick_best_visual (screen, prefer_writable_cells, False);
93 else if (vclass == MONO_VISUAL)
95 result = pick_mono_visual (screen);
96 if (!result && verbose_p)
97 fprintf (stderr, "%s: no monochrome visuals.\n", progname);
99 else if (vclass == GRAY_VISUAL)
101 if (prefer_writable_cells)
102 result = pick_best_visual_of_class (screen, GrayScale);
104 result = pick_best_visual_of_class (screen, StaticGray);
106 result = pick_best_visual_of_class (screen, GrayScale);
107 if (!result && verbose_p)
108 fprintf (stderr, "%s: no GrayScale or StaticGray visuals.\n",
111 else if (vclass == COLOR_VISUAL)
114 /* First see if the default visual will do. */
115 result = DefaultVisualOfScreen (screen);
116 class = visual_class(screen, result);
117 if (class != TrueColor &&
118 class != PseudoColor &&
119 class != DirectColor &&
120 class != StaticColor)
122 if (result && visual_depth(screen, result) <= 1)
125 /* Else, find the best non-default color visual */
127 result = pick_best_visual (screen, prefer_writable_cells, True);
129 if (!result && verbose_p)
130 fprintf (stderr, "%s: no color visuals.\n", progname);
132 else if (vclass == GL_VISUAL)
134 Visual *visual = pick_best_gl_visual (screen);
138 fprintf (stderr, "%s: no visual suitable for GL.\n", progname, v);
140 else if (vclass == SPECIFIC_VISUAL)
142 result = id_to_visual (screen, id);
143 if (!result && verbose_p)
144 fprintf (stderr, "%s: no visual with id 0x%x.\n", progname,
149 Visual *visual = pick_best_visual_of_class (screen, vclass);
153 fprintf (stderr, "%s: no visual of class %s.\n", progname, v);
161 get_visual_resource (Screen *screen, char *name, char *class,
162 Bool prefer_writable_cells)
164 char *string = get_string_resource (name, class);
165 Visual *v = get_visual (screen, string, prefer_writable_cells, True);
171 return DefaultVisualOfScreen (screen);
176 pick_best_visual (Screen *screen, Bool prefer_writable_cells, Bool color_only)
180 if (!prefer_writable_cells)
182 /* If we don't prefer writable cells, then the "best" visual is the one
183 on which we can allocate the largest range and number of colors.
185 Therefore, a TrueColor visual which is at least 16 bits deep is best.
186 (The assumption here being that a TrueColor of less than 16 bits is
187 really just a PseudoColor visual with a pre-allocated color cube.)
189 The next best thing is a PseudoColor visual of any type. After that
190 come the non-colormappable visuals, and non-color visuals.
192 if ((visual = pick_best_visual_of_class (screen, TrueColor)) &&
193 visual_depth (screen, visual) >= 16)
197 #define TRY_CLASS(CLASS) \
198 if ((visual = pick_best_visual_of_class (screen, CLASS)) && \
199 (!color_only || visual_depth(screen, visual) > 1)) \
201 TRY_CLASS(PseudoColor);
202 TRY_CLASS(TrueColor);
203 TRY_CLASS(DirectColor);
204 TRY_CLASS(StaticColor);
207 TRY_CLASS(GrayScale);
208 TRY_CLASS(StaticGray);
212 visual = DefaultVisualOfScreen (screen);
213 if (!color_only || visual_depth(screen, visual) > 1)
220 pick_mono_visual (Screen *screen)
222 Display *dpy = DisplayOfScreen (screen);
223 XVisualInfo vi_in, *vi_out;
227 vi_in.screen = screen_number (screen);
228 vi_out = XGetVisualInfo (dpy, (VisualDepthMask | VisualScreenMask),
232 Visual *v = (out_count > 0 ? vi_out [0].visual : 0);
233 if (v && vi_out[0].depth != 1)
235 XFree ((char *) vi_out);
244 pick_best_visual_of_class (Screen *screen, int visual_class)
246 /* The best visual of a class is the one which on which we can allocate
247 the largest range and number of colors, which means the one with the
248 greatest depth and number of cells.
250 (But actually, for XDaliClock, all visuals of the same class are
251 probably equivalent - either we have writable cells or we don't.)
253 Display *dpy = DisplayOfScreen (screen);
254 XVisualInfo vi_in, *vi_out;
257 vi_in.class = visual_class;
258 vi_in.screen = screen_number (screen);
259 vi_out = XGetVisualInfo (dpy, (VisualClassMask | VisualScreenMask),
263 /* choose the 'best' one, if multiple */
266 /* for (i = 0, best = 0; i < out_count; i++) */
267 for (i = out_count-1, best = i; i >= 0; i--) /* go backwards */
268 /* It's better if it's deeper, or if it's the same depth with
269 more cells (does that ever happen? Well, it could...) */
270 if ((vi_out [i].depth > vi_out [best].depth) ||
271 ((vi_out [i].depth == vi_out [best].depth) &&
272 (vi_out [i].colormap_size > vi_out [best].colormap_size)))
274 visual = (best < out_count ? vi_out [best].visual : 0);
275 XFree ((char *) vi_out);
283 pick_best_gl_visual (Screen *screen)
285 /* The best visual for GL is a TrueColor visual that is half as deep as
286 the screen. If such a thing doesn't exist, then TrueColor is best.
287 Failing that, the deepest available color visual is best.
289 Compare this function to get_gl_visual() in visual-gl.c.
290 This function tries to find the best GL visual using Xlib calls,
291 whereas that function does the same thing using GLX calls.
293 Display *dpy = DisplayOfScreen (screen);
294 XVisualInfo vi_in, *vi_out;
299 int *depths = XListDepths (dpy, screen_number (screen), &ndepths);
300 int screen_depth = depths[ndepths];
303 vi_in.class = TrueColor;
304 vi_in.screen = screen_number (screen);
305 vi_in.depth = screen_depth / 2;
306 vi_out = XGetVisualInfo (dpy, (VisualClassMask | VisualScreenMask |
310 result = vi_out[0].visual;
313 XFree ((char *) vi_out);
315 if (!result && screen_depth > 24)
317 /* If it's a 32-deep screen and we didn't find a depth-16 visual,
318 see if there's a depth-12 visual. */
319 vi_in.class = TrueColor;
320 vi_in.screen = screen_number (screen);
322 vi_out = XGetVisualInfo (dpy, (VisualClassMask | VisualScreenMask |
326 result = vi_out[0].visual;
330 /* No half-depth TrueColor? Ok, try for any TrueColor (the deepest.) */
331 result = pick_best_visual_of_class (screen, TrueColor);
334 /* No TrueColor? Ok, try for anything. */
335 result = pick_best_visual (screen, False, False);
342 id_to_visual (Screen *screen, int id)
344 Display *dpy = DisplayOfScreen (screen);
345 XVisualInfo vi_in, *vi_out;
347 vi_in.screen = screen_number (screen);
349 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualIDMask),
353 Visual *v = vi_out[0].visual;
354 XFree ((char *) vi_out);
361 visual_depth (Screen *screen, Visual *visual)
363 Display *dpy = DisplayOfScreen (screen);
364 XVisualInfo vi_in, *vi_out;
366 vi_in.screen = screen_number (screen);
367 vi_in.visualid = XVisualIDFromVisual (visual);
368 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
370 if (! vi_out) abort ();
371 d = vi_out [0].depth;
372 XFree ((char *) vi_out);
378 /* You very probably don't want to be using this.
379 Pixmap depth doesn't refer to the depths of pixmaps, but rather, to
380 the depth of protocol-level on-the-wire pixmap data, that is, XImages.
381 To get this info, you should be looking at XImage->bits_per_pixel
382 instead. (And allocating the data for your XImage structures by
383 multiplying ximage->bytes_per_line by ximage->height.)
386 visual_pixmap_depth (Screen *screen, Visual *visual)
388 Display *dpy = DisplayOfScreen (screen);
389 int vdepth = visual_depth (screen, visual);
392 XPixmapFormatValues *pfv = XListPixmapFormats (dpy, &pfvc);
394 /* Return the first matching depth in the pixmap formats. If there are no
395 matching pixmap formats (which shouldn't be able to happen at all) then
396 return the visual depth instead. */
397 for (i = 0; i < pfvc; i++)
398 if (pfv[i].depth == vdepth)
400 pdepth = pfv[i].bits_per_pixel;
411 visual_class (Screen *screen, Visual *visual)
413 Display *dpy = DisplayOfScreen (screen);
414 XVisualInfo vi_in, *vi_out;
416 vi_in.screen = screen_number (screen);
417 vi_in.visualid = XVisualIDFromVisual (visual);
418 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
420 if (! vi_out) abort ();
421 c = vi_out [0].class;
422 XFree ((char *) vi_out);
427 has_writable_cells (Screen *screen, Visual *visual)
429 switch (visual_class (screen, visual))
431 case GrayScale: /* Mappable grays. */
432 case PseudoColor: /* Mappable colors. */
434 case StaticGray: /* Fixed grays. */
435 case TrueColor: /* Fixed colors. */
436 case StaticColor: /* (What's the difference again?) */
437 case DirectColor: /* DirectColor visuals are like TrueColor, but have
438 three colormaps - one for each component of RGB.
448 describe_visual (FILE *f, Screen *screen, Visual *visual, Bool private_cmap_p)
451 Display *dpy = DisplayOfScreen (screen);
452 XVisualInfo vi_in, *vi_out;
454 vi_in.screen = screen_number (screen);
455 vi_in.visualid = XVisualIDFromVisual (visual);
456 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualIDMask),
458 if (! vi_out) abort ();
460 sprintf(n, "%3d", vi_out->colormap_size);
462 strcpy(n, "default");
464 fprintf (f, "0x%02x (%s depth: %2d, cmap: %s)\n",
465 (unsigned int) vi_out->visualid,
466 (vi_out->class == StaticGray ? "StaticGray, " :
467 vi_out->class == StaticColor ? "StaticColor," :
468 vi_out->class == TrueColor ? "TrueColor, " :
469 vi_out->class == GrayScale ? "GrayScale, " :
470 vi_out->class == PseudoColor ? "PseudoColor," :
471 vi_out->class == DirectColor ? "DirectColor," :
474 XFree ((char *) vi_out);
478 screen_number (Screen *screen)
480 Display *dpy = DisplayOfScreen (screen);
482 for (i = 0; i < ScreenCount (dpy); i++)
483 if (ScreenOfDisplay (dpy, i) == screen)
490 visual_cells (Screen *screen, Visual *visual)
492 Display *dpy = DisplayOfScreen (screen);
493 XVisualInfo vi_in, *vi_out;
495 vi_in.screen = screen_number (screen);
496 vi_in.visualid = XVisualIDFromVisual (visual);
497 vi_out = XGetVisualInfo (dpy, VisualScreenMask|VisualIDMask,
499 if (! vi_out) abort ();
500 c = vi_out [0].colormap_size;
501 XFree ((char *) vi_out);
506 find_similar_visual(Screen *screen, Visual *old_visual)
508 Display *dpy = DisplayOfScreen (screen);
509 XVisualInfo vi_in, *vi_out;
513 vi_in.screen = screen_number (screen);
514 vi_in.class = visual_class (screen, old_visual);
515 vi_in.depth = visual_depth (screen, old_visual);
517 /* Look for a visual of the same class and depth.
519 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualClassMask |
522 if (vi_out && out_count > 0)
523 result = vi_out[0].visual;
524 if (vi_out) XFree (vi_out);
527 /* Failing that, look for a visual of the same class.
531 vi_out = XGetVisualInfo (dpy, (VisualScreenMask | VisualClassMask),
533 if (vi_out && out_count > 0)
534 result = vi_out[0].visual;
535 if (vi_out) XFree (vi_out);
539 /* Failing that, return the default visual. */
541 result = DefaultVisualOfScreen (screen);